1
|
Trofimova IN, Gaykalova AA. Emotionality vs. Other Biobehavioural Traits: A Look at Neurochemical Biomarkers for Their Differentiation. Front Psychol 2021; 12:781631. [PMID: 34987450 PMCID: PMC8720768 DOI: 10.3389/fpsyg.2021.781631] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 12/01/2021] [Indexed: 12/15/2022] Open
Abstract
This review highlights the differential contributions of multiple neurochemical systems to temperament traits related and those that are unrelated to emotionality, even though these systems have a significant overlap. The difference in neurochemical biomarkers of these traits is analysed from the perspective of the neurochemical model, Functional Ensemble of Temperament (FET) that uses multi-marker and constructivism principles. Special attention is given to a differential contribution of hypothalamic-pituitary hormones and opioid neuropeptides implicated in both emotional and non-emotional regulation. The review highlights the role of the mu-opioid receptor system in dispositional emotional valence and the role of the kappa-opioid system in dispositional perceptual and behavioural alertness. These opioid receptor (OR) systems, microbiota and cytokines are produced in three neuroanatomically distinct complexes in the brain and the body, which all together integrate dispositional emotionality. In contrast, hormones could be seen as neurochemical biomarkers of non-emotional aspects of behavioural regulation related to the construction of behaviour in fast-changing and current situations. As examples of the role of hormones, the review summarised their contribution to temperament traits of Sensation Seeking (SS) and Empathy (EMP), which FET considers as non-emotionality traits related to behavioural orientation. SS is presented here as based on (higher) testosterone (fluctuating), adrenaline and (low) cortisol systems, and EMP, as based on (higher) oxytocin, reciprocally coupled with vasopressin and (lower) testosterone. Due to the involvement of gonadal hormones, there are sex and age differences in these traits that could be explained by evolutionary theory. There are, therefore, specific neurochemical biomarkers differentiating (OR-based) dispositional emotionality and (hormones-based) body's regulation in fast-changing events. Here we propose to consider dispositional emotionality associated with OR systems as emotionality in a true sense, whereas to consider hormonal ensembles regulating SS and EMP as systems of behavioural orientation and not emotionality.
Collapse
Affiliation(s)
- Irina N. Trofimova
- Laboratory of Collective Intelligence, Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada
| | | |
Collapse
|
2
|
TODOROKI K, NAKANO M, YOSHIDA H, NOHTA H, YAMAGUCHI M. Sensitive and Selective LC Determination of 5-Hydroxyindoles Through Online Electrochemical Fluorescence Derivatization Using Benzylamine. CHROMATOGRAPHY 2021. [DOI: 10.15583/jpchrom.2020.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
| | - Masaki NAKANO
- Faculty of Pharmaceutical Sciences, Fukuoka University
| | | | - Hitoshi NOHTA
- Faculty of Pharmaceutical Sciences, Fukuoka University
| | - Masatoshi YAMAGUCHI
- Department of Pharmaceutical Sciences, International University of Health and Welfare
| |
Collapse
|
3
|
Ahmadian-Moghadam H, Sadat-Shirazi MS, Seifi F, Niknamfar S, Akbarabadi A, Toolee H, Zarrindast MR. Transgenerational influence of parental morphine exposure on pain perception, anxiety-like behavior and passive avoidance memory among male and female offspring of Wistar rats. EXCLI JOURNAL 2019; 18:1019-1036. [PMID: 31762726 PMCID: PMC6868917 DOI: 10.17179/excli2019-1845] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 10/29/2019] [Indexed: 12/11/2022]
Abstract
Accumulating evidence suggests that epigenetic mechanisms play an important role in the formation and maintenance of memory within the brain. Moreover, the effect of parental drug-exposure before gestation on behavioral state of offspring has been little studied. The main objective of the current study is to evaluate the effect of parental morphine exposure on avoidance memory, morphine preference and anxiety-like behavior of offspring. The total of 32 males and 32 females were used for mating. The animals were treated with morphine. The offspring according to their parental morphine treatment was divided into four groups (n=16) including paternally treated, maternally treated, both of parents treated and naïve animals. The pain perception, anxiety-like behavior, and avoidance memory were evaluated in the offspring. In the current study, the total of 256 offspring was used for the experiments (4 tasks × 4 groups of offspring × 8 female offspring × 8 male offspring). The finding revealed that the avoidance memory and visceral pain were reduced significantly in male and female offspring with at least one morphine-treated parent. Moreover, anxiety-like behavior was reduced significantly in the male offspring with at least one morphine-treated parent. While anxiety-like behavior was increased significantly in female offspring that were treated by morphine either maternally or both of parents. The data revealed that the endogenous opioid system may be altered in the offspring of morphine-treated parent(s), and epigenetic role could be important. However, analysis of variance signified the important role of maternal inheritance.
Collapse
Affiliation(s)
- Hamid Ahmadian-Moghadam
- Iranian National Center for Addiction Studies, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Fereshteh Seifi
- Biology Department, Faculty of Biological Sciences, Islamic Azad University, North Tehran Branch, Tehran, Iran
| | - Saba Niknamfar
- Biology Department, Faculty of Biological Sciences, Islamic Azad University, North Tehran Branch, Tehran, Iran
| | - Ardeshir Akbarabadi
- Iranian National Center for Addiction Studies, Tehran University of Medical Sciences, Tehran, Iran
- Department of Veterinary Medicine, Garmsar Branch, Islamic Azad University, Garmsar, Iran
| | - Heidar Toolee
- Department of Anatomy, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad-Reza Zarrindast
- Iranian National Center for Addiction Studies, Tehran University of Medical Sciences, Tehran, Iran
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
- Endocrinology and Metabolism Research Institute, Tehran University of Medical Science, Tehran, Iran
| |
Collapse
|
4
|
Concerted derivatization and concentration method with dispersive liquid–liquid microextraction for liquid chromatographic analysis of 5-hydroxyindoles in human serum. Talanta 2013; 117:27-31. [DOI: 10.1016/j.talanta.2013.08.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 08/22/2013] [Accepted: 08/22/2013] [Indexed: 11/20/2022]
|
5
|
Shahidi S, Hashemi-Firouzi N. Role of 5-HT7 receptors in the anxiety-like behavior in naloxone-induced withdrawal symptoms in mice. NEUROCHEM J+ 2013. [DOI: 10.1134/s1819712413040107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
6
|
Bloms-Funke P, Dremencov E, Cremers TIFH, Tzschentke TM. Tramadol increases extracellular levels of serotonin and noradrenaline as measured by in vivo microdialysis in the ventral hippocampus of freely-moving rats. Neurosci Lett 2010; 490:191-5. [PMID: 21195741 DOI: 10.1016/j.neulet.2010.12.049] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 12/07/2010] [Accepted: 12/21/2010] [Indexed: 11/29/2022]
Abstract
Tramadol is an atypical opioid with monoamine re-uptake inhibition properties. The aim of the current study was to compare, using in vivo microdialysis, the effect of tramadol on extracellular serotonin (5-HT) and noradrenaline (NA) levels in the rat ventral hippocampus with the effects of the dual 5-HT/NA inhibitors (SNRIs) duloxetine and venlafaxine, the tricyclic antidepressant clomipramine, the selective 5-HT re-uptake inhibitor (SSRI) citalopram, and the selective NA re-uptake inhibitor (NRI) reboxetine. It was found that tramadol, duloxetine and venlafaxine increased extracellular levels of both, 5-HT and NA, in a dose-dependent manner. Clomipramine also increased extracellular 5-HT and NA levels, however not dose-dependently in the tested dose range. Citalopram selectively increased extracellular 5-HT levels. Reboxetine increased extracellular NA levels and also to a minimal degree 5-HT levels. It can be concluded that, albeit less efficacious, the effects of tramadol on serotonergic and noradrenergic neurotransmission resemble those of the dual 5-HT and NA re-uptake inhibitors duloxetine, venlafaxine, and clomipramine, and are different from those of the SSRI citalopram and the NRI reboxetine.
Collapse
Affiliation(s)
- P Bloms-Funke
- Grünenthal GmbH, Global Preclinical Research and Development, 52099 Aachen, Germany.
| | | | | | | |
Collapse
|
7
|
Hipólito L, Sánchez-Catalán MJ, Zanolini I, Polache A, Granero L. Shell/core differences in mu- and delta-opioid receptor modulation of dopamine efflux in nucleus accumbens. Neuropharmacology 2008; 55:183-9. [PMID: 18582908 DOI: 10.1016/j.neuropharm.2008.05.012] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Revised: 04/16/2008] [Accepted: 05/11/2008] [Indexed: 10/22/2022]
Abstract
The mu- and delta-opioid receptors located at the terminal level in nucleus accumbens are involved in the opiate modulation of dopamine release in this brain area. However, recent studies suggest that the effects of opioid drugs on the core subregion of nucleus accumbens may completely differ from those observed in the shell. We used in vivo microdialysis to simultaneously apply selective mu- and delta-opioid receptor agonists and to measure extracellular levels of dopamine in three subregions of the accumbens, namely shell, core, and the transition zone between them. The regional analysis of these subregions of the accumbens demonstrated that basal levels of dopamine and its metabolites were higher in the core, and decreased from this subregion to the shell. Retrodialysis application to the core of both the selective mu-receptor agonist ([D-Ala(2), N-Me-Phe(4), Gly(5)-ol]-enkephalin (DAMGO) (1 micromol/L)) and of the selective delta-opioid receptor agonist ([D-Pen(2), D-Pen(5)]-enkephalin (DPDPE) (50 nmol/L)) increased the dialysate levels of dopamine. However, the application of these drugs to the shell significantly reduced the dopamine levels in this subregion. Local application of the same doses of these drugs in the transition zone between the shell and the core did not significantly affect the dopamine levels in dialysates. These results suggest that the opioid circuits modulating dopaminergic activity in the shell could differ from those in the core of the nucleus accumbens.
Collapse
Affiliation(s)
- Lucía Hipólito
- Departament de Farmacia i Tecnología Farmacèutica, Universitat de València, Avda Vicente Andrés Estellés s/n, 46100 Burjassot, Spain
| | | | | | | | | |
Collapse
|
8
|
Abstract
Opiate drugs alter cognitive performance and influence hippocampal excitability, including long-term potentiation (LTP) and seizure activity. The dentate gyrus (DG) contains two major opioid peptides, enkephalins and dynorphins, which have opposing effects on excitability. Enkephalins preferentially bind to delta- and mu-opioid receptors (DORs and MORs) while dynorphins preferentially bind to kappa-opioid receptors (KORs). Opioid receptors can also be activated by exogenous opiate drugs such as the MOR agonist morphine. Enkephalins are contained in the mossy fiber pathway, in the lateral perforant path (PP) and in scattered GABAergic interneurons. MORs and DORs are predominantly in distinct subpopulations of GABAergic interneurons known to inhibit granule cells, and are present at low levels within granule cells. MOR and DOR agonists increase excitability and facilitate LTP in the molecular layer. Anatomical and physiological evidence is consistent with somatodendritic and axon terminal targeting of both MORs and DORs. Dynorphins are in the granule cells, most abundantly in mossy fibers but also in dendrites. KORs have been localized to granule cell mossy fibers, supramammillary afferents to granule cells, and PP terminals. KOR agonists, including endogenous dynorphins, diminish the induction of LTP. Recent evidence indicates that opiates and opioids also modulate other processes in the hippocampal formation, including adult neurogenesis, the actions of gonadal hormones, and development of neonatal transmitter systems.
Collapse
Affiliation(s)
- Carrie T Drake
- Division of Neurobiology, Department of Neurology and Neuroscience, Weill-Cornell Medical College, 411 East 69th Street, New York, NY 10021, USA
| | | | | |
Collapse
|
9
|
Todoroki K, Nakashima Y, Yoshida H, Nohta H, Yamaguchi M. Online photocatalytic device for highly selective pre-column fluorescence derivatization of 5-hydroxyindoles with benzylamine. Anal Chim Acta 2006. [DOI: 10.1016/j.aca.2005.08.076] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
10
|
Vitale G, Arletti R, Sandrini M. Acute noise stress analgesia in relation to 5-HT2 and μ-opioid receptor changes in the frontal cortex of young mice. Life Sci 2005; 77:2500-13. [PMID: 15935399 DOI: 10.1016/j.lfs.2005.01.031] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2004] [Accepted: 01/11/2005] [Indexed: 12/17/2022]
Abstract
A number of studies have reported that exposure to stress provoked behavioural changes, including analgesia, in rodents. Differences have been observed in these responses to different types of stress and a link between hormones and neurotransmitters proposed. We studied the effect of acute noise stress on nociception and the possible changes in the serotonergic and opioidergic systems in young mice of both sexes. Naloxone pre-treatment was also investigated. Noise stress was produced by a sound source, nociception was measured by the hot-plate test and binding characteristics were evaluated by a radioligand binding technique using membrane preparation from the total frontal cortex. Acute noise stress provoked an antinociceptive effect, associated with an increase in plasma corticosterone levels, a decrease in the number of 5-HT2 receptors in stressed male and female mice and a decrease in the number of mu receptors in both sexes. The behavioural and biochemical effects were antagonized by 1 mg/kg of naloxone. Acute noise stress behaves like other types of stress on nociception. The opioidergic system seems to be involved in this behaviour but also the serotonergic system may play a role. Sex differences were detected in the number of 5-HT2 and mu receptors between male and female mice not subjected to stress, while the percentage decrease in 5-HT2 and mu receptors did not differ significantly between the two sexes.
Collapse
MESH Headings
- Animals
- Behavior, Animal/physiology
- Binding Sites
- Cell Membrane/metabolism
- Cerebral Cortex/metabolism
- Corticosterone/blood
- Female
- Male
- Mice
- Motor Activity/physiology
- Narcotic Antagonists/pharmacology
- Noise/adverse effects
- Pain Measurement
- Radioligand Assay
- Receptors, Opioid, mu/antagonists & inhibitors
- Receptors, Opioid, mu/metabolism
- Receptors, Serotonin, 5-HT2/metabolism
- Serotonin 5-HT2 Receptor Antagonists
- Serotonin Antagonists/pharmacology
- Stress, Physiological/etiology
- Stress, Physiological/metabolism
- Stress, Physiological/physiopathology
Collapse
Affiliation(s)
- Giovanni Vitale
- Department of Biomedical Science, Section of Pharmacology, University of Modena and Reggio Emilia, via G. Campi 287, 41100 Modena, Italy
| | | | | |
Collapse
|
11
|
Yoshitake T, Fujino K, Kehr J, Ishida J, Nohta H, Yamaguchi M. Simultaneous determination of norepinephrine, serotonin, and 5-hydroxyindole-3-acetic acid in microdialysis samples from rat brain by microbore column liquid chromatography with fluorescence detection following derivatization with benzylamine. Anal Biochem 2003; 312:125-33. [PMID: 12531196 DOI: 10.1016/s0003-2697(02)00435-9] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A microbore column liquid chromatographic method for the simultaneous determination of norepinephrine (NE), serotonin (5-HT), and 5-hydroxyindole-3-acetic acid (5HIAA) in microdialysis samples from rat brain is described. The method is based on precolumn derivatization of NE, 5HT, and 5HIAA with benzylamine in the presence of potassium hexacyanoferrate(III) resulting in the corresponding highly fluorescent and stable benzoxazole derivatives. A 15-microl sample was mixed with 15 microl derivatization reagent solution containing 0.3M 3-cyclohexylaminopropanesulfonic acid buffer (pH 12.0), 0.5M benzylamine, 10mM potassium hexacyanoferrate(III), and methanol (1/1/1/12, v/v/v/v). The derivatization was carried out at 50 degrees C for 20 min. The benzylamine derivatives of NE, 5HT, and 5HIAA were separated on a reversed-phase column (100 x 1.0mm i.d., packed with C18 silica, 5 microm) within 30 min. The mobile phase consisted of 15 mM acetate buffer (pH 5.0) and acetonitrile (31%, v/v); the flow rate was 50 microl/min. The detection limits (signal-to-noise ratio of 3) for NE, 5HT, and 5HIAA in the injection volume of 20 microl were 90, 210, and 260 amol, respectively. Microdialysis samples were collected in 7.5-min intervals from the probes implanted in the hippocampus and prefrontal cortex of awake rats. The basal levels of NE, 5HT, and 5HIAA in the dialysates from the hippocampus were 4.2+/-0.5, 4.9+/-0.6, and 934.1 +/- 63.4 fmol/20 microl, and those from the prefrontal cortex were 6.0+/-1.2,5.51.3, and 669.1 +/- 96.0 fmol/20 microl (mean +/- SE, n=25), respectively. The NE and 5HT levels were altered by perfusion of high-potassium or low-calcium solution and following antidepressant drugs imipramine and desipramine. It is concluded that the new fluorescence derivatization method in combination with microbore column liquid chromatography allows the simultaneous determination of NE, 5HT, and 5HIAA in the microdialysis samples at higher sensitivity, providing easier maintenance in routine use than that achieved by high-performance liquid chromatographic methods with electrochemical detection.
Collapse
Affiliation(s)
- Takashi Yoshitake
- Department of Neuroscience, Karolinska Institutet, S-171 77 Stockholm, Sweden
| | | | | | | | | | | |
Collapse
|
12
|
Vilpoux C, Carpentier C, Leroux-Nicollet I, Naudon L, Costentin J. Differential effects of chronic antidepressant treatments on micro- and delta-opioid receptors in rat brain. Eur J Pharmacol 2002; 443:85-93. [PMID: 12044796 DOI: 10.1016/s0014-2999(02)01585-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We performed an autoradiographic study of [D-Ala(2),MePhe(4),Gly-ol(5)]enkephalin (DAMGO)-sensitive [(3)H]naloxone binding to micro-opioid receptors and of [(3)H][D-Pen(2),D-Pen(5)]enkephalin (DPDPE) binding to delta-opioid receptors in the rat brain after 4- or 21-day treatments with paroxetine, reboxetine and moclobemide to investigate the participation of these receptors in the adaptive mechanisms occurring during the delay of action of new generation antidepressants. Paroxetine increased micro-opioid receptor binding site density in cingulate and insular cortices, dorsal endopiriform nucleus (4 days) and olfactory tubercle (21 days) and decreased it in thalamus (21 days). Reboxetine increased it in amygdala (4 days), hippocampus and thalamus (21 days) and decreased it in dorsal raphe (4 days). Moclobemide increased it in hippocampus (4 days) and decreased it in anterior olfactory nucleus, frontal cortex, amygdala and hypothalamus (21 days). Moclobemide increased delta-opioid receptor binding site density in frontal cortex and amygdala (4 days) and decreased it in amygdala and colliculi (21 days). Opioid receptors displayed distinct patterns of adaptations in response to the three antidepressants studied.
Collapse
MESH Headings
- Animals
- Antidepressive Agents/administration & dosage
- Antidepressive Agents/pharmacology
- Autoradiography
- Binding Sites
- Brain/anatomy & histology
- Brain/metabolism
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/pharmacology
- Enkephalin, D-Penicillamine (2,5)-/pharmacology
- Injections, Intraperitoneal
- Male
- Moclobemide/administration & dosage
- Moclobemide/pharmacology
- Morpholines/administration & dosage
- Morpholines/pharmacology
- Paroxetine/administration & dosage
- Paroxetine/pharmacology
- Rats
- Rats, Sprague-Dawley
- Reboxetine
- Receptors, Opioid, delta/drug effects
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, mu/drug effects
- Receptors, Opioid, mu/metabolism
- Time Factors
Collapse
Affiliation(s)
- Catherine Vilpoux
- Unité de Neuropsychopharmacologie Expérimentale, CNRS UPRESA 6036, IFRMP No. 23, UFR de Médecine-Pharmacie, 22 Bd. Gambetta, 76 183 Rouen, Cedex, France
| | | | | | | | | |
Collapse
|
13
|
Nauli SM, Maher TJ, Pearce WJ, Ally A. Effects of opioid receptor activation on cardiovascular responses and extracellular monoamines within the rostral ventrolateral medulla during static contraction of skeletal muscle. Neurosci Res 2001; 41:373-83. [PMID: 11755224 DOI: 10.1016/s0168-0102(01)00296-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
During static muscle contraction, activation of opioid receptors alters the extracellular glutamate concentrations within the rostral ventrolateral medulla (RVLM). In addition, microdialysis of glutamate in the ventrolateral medulla (VLM) increases the release of norepinephrine (NE), dopamine (DA), and serotonin (5-HT). Therefore, we hypothesized that extracellular concentrations of these monoamines as well as cardiovascular responses during static skeletal muscle contraction would be modulated following administration of [D-Ala(2)]methionine enkephalinamide (DAME), an opioid receptor agonist, into the RVLM. Microdialysis of 100 microM DAME into the RVLM of 10 rats significantly (P<0.01) decreased extracellular levels (in pg/10 microl) of NE (from 3.3+/-0.3 to 1.9+/-0.3), DA (from 5.5+/-0.2 to 3.7+/-0.3), and 5-HT (from 6.1+/-0.8 to 3.6+/-0.2) during static exercise. After microdialysis of DAME, the exercise pressor reflex also significantly (P<0.01) decreased mean arterial pressure (MAP) by 13+/-3 mmHg and heart rate (HR) by 16+/-6 bpm, compared with control (MAP=22+/-4 mmHg and HR=31+/-7 bpm). Subsequently, after 30 min microdialysis of naloxone, an opioid receptor antagonist, muscle contraction increased the extracellular monoamine levels (in pg/10 microl, 3.8+/-0.3 NE; 5.2+/-0.3 DA; and 5.5+/-0.4 5-HT) similar to the control groups and evoked a reversal of cardiovascular responses. Similarly, 30 min of microdialyzing naloxone, added to the perfusing medium containing DAME, reversed the attenuating effects of DAME on monoamines, MAP, and HR during a muscle contraction. Furthermore, microdialysis of 100 microM naloxone alone for 30 min potentiated cardiovascular responses and monoamine levels during a muscle contraction. In summary, the present data demonstrates that microdialysis of DAME into RVLM attenuates the exercise pressor reflex mediated increases in MAP, HR and extracellular levels of biogenic monoamines. A subsequent microdialysis of naloxone reversed the effects suggesting that an opioidergic mechanism within RVLM modulates the exercise pressor reflex. Overall, the present study provides further insights into the opioidergic modulation of the exercise pressor reflex.
Collapse
Affiliation(s)
- S M Nauli
- Department of Physiology and Pharmacology, Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
| | | | | | | |
Collapse
|
14
|
Li JY, Wong CH, Huang EY, Lin YC, Chen YL, Tan PP, Chen JC. Modulations of Spinal Serotonin Activity Affect the Development of Morphine Tolerance. Anesth Analg 2001; 92:1563-8. [PMID: 11375847 DOI: 10.1097/00000539-200106000-00043] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
To test whether modulations of spinal serotonin (5-HT) levels would affect the development of morphine tolerance, we treated rats with either intrathecal 5-HT or 5,7-dihydroxytryptamine (5,7-DHT; a 5-HT neurotoxin) in addition to systemic infusion with morphine (2 mg x kg(-1) x h(-1)). Continuous infusion of 5-HT (10 microg x 6 microL(-1) x h(-1)) into the lumbar subarachnoid space of rats for 9 h accelerated the development of morphine tolerance. The area under the curve for the tail-flick latency test was 454.1 +/- 35.1 in the Sham Control group vs 327.6 +/- 41.0 in the 5-HT-Infused group. mu-opioid receptor binding in the lumbar spinal cord showed a decrease in the Bmax (maximal binding -46.5%), but not the binding affinity (Kd), in 5-HT-infused rats. However, intrathecal injection of 5,7-DHT (50 microg), which resulted in a 48% reduction in 5-HT and 51% reduction in 5-hydroxyindoleacetic acid concentrations, led to an attenuation of morphine tolerance (the area under the curve was 613.0 +/- 24.7 in the 5,7-DHT-Lesioned group). The binding study indicated that the affinity of lumbar micro-opioid receptors decreased 196% in 5-HT-depleted rats, whereas there was no effect on apparent binding. The infusion of 5-HT (10 microg x 6 microL(-1) x h(-1)) was not analgesic and the 5,7-DHT-induced lesion did not affect acute morphine-induced analgesia. We conclude that activity of spinal 5-HT-containing neurons plays a crucial role during the development of morphine tolerance.
Collapse
Affiliation(s)
- J Y Li
- Department of Anesthesiology, Chang-Gung Memorial Hospital, Taiwan, ROC
| | | | | | | | | | | | | |
Collapse
|
15
|
Sandrini M, Romualdi P, Vitale G, Morelli G, Capobianco A, Pini LA, Candeletti S. The effect of a paracetamol and morphine combination on dynorphin A levels in the rat brain. Biochem Pharmacol 2001; 61:1409-16. [PMID: 11331077 DOI: 10.1016/s0006-2952(01)00623-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The purpose of this study was to find out whether the combination of inactive doses of paracetamol (PARA) and morphine was able to change dynorphin (DYN) A levels, evaluated by radioimmunoassay, and whether naloxone or [(-)-2-(3 furylmethyl)-normetazocine] (MR 2266), a kappa-opioid antagonist, modifies or prevents the activity of this combination on nociception and on DYN levels. The work was suggested by our previous findings which demonstrated that inactive doses of PARA and morphine, when given in combination, share an antinociceptive effect, and that PARA, at antinociceptive doses, decreases DYN levels in the frontal cortex, thus indicating a selective action within the CNS. Our present results demonstrate that the combination of inactive doses of PARA (100 mg/kg) and morphine (3 mg/kg) is just as effective in decreasing the levels of DYN A as full antinociceptive doses of PARA or morphine alone in the frontal cortex of the rat. The values, expressed in pmol/g tissue, were: control = 2.83 +/- 0.20; paracetamol (100) = 2.60 +/- 0.23; morphine (3) = 2.73 +/- 0.24; paracetamol + morphine = 1.34 + 0.16 (P < 0.05). The decrease was partially antagonised by MR 2266, but not by naloxone, suggesting that the activity of PARA and morphine in combination on DYN A levels could be mediated, at least in part, through kappa-receptors, although other systems may be involved. On the other hand, both naloxone and MR 2266 prevented the antinociceptive effect of the combination in the hot plate test. All our experimental data suggest that PARA and morphine in combination exert their antinociceptive effect through the opioidergic system, which in turn may cause a decrease in DYN levels in the CNS of the rat.
Collapse
Affiliation(s)
- M Sandrini
- Department of Biomedical Science, Pharmacology Section, University of Modena, Via Campi 287, 1-4100, Modena, Italy.
| | | | | | | | | | | | | |
Collapse
|
16
|
Bergqvist PB, Bouchard C, Blier P. Effect of long-term administration of antidepressant treatments on serotonin release in brain regions involved in obsessive-compulsive disorder. Biol Psychiatry 1999; 45:164-74. [PMID: 9951563 DOI: 10.1016/s0006-3223(98)00154-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Among all antidepressant treatments, including electroconvulsive shock (ECS) therapy and monoamine oxidase inhibitors (MAOIs), only the selective serotonin (5-HT) reuptake inhibitors (SSRIs) exert a clear therapeutic effect in obsessive-compulsive disorder (OCD). An 8-week, but not a 3-week treatment with the SSRI paroxetine results in an increased electrically evoked [3H]5-HT release and a desensitization of 5-HT autoreceptors in the guinea pig orbitofrontal cortex, a brain region implicated in OCD. METHODS In the present study, the effect of long-term treatment with the SSRI fluoxetine, ECS, and the reversible type A MAOI moclobemide was investigated on evoked [3H]5-HT release from preloaded guinea pig brain slices prepared from the hypothalamus, cingulate cortex, and orbitofrontal cortex. RESULTS Fluoxetine treatment yielded an enhanced [3H]5-HT release in the three brain areas, but a desensitization of the 5-HT autoreceptor only in the hypothalamus and orbitofrontal cortex. ECS treatment did not result in any alteration of the electrically evoked [3H]5-HT release or of 5-HT autoreceptor sensitivity in any of the brain regions. Moclobemide increased [3H]5-HT release only in the orbitofrontal cortex without any alteration in the 5-HT autoreceptor sensitivity. CONCLUSIONS These findings indicate that only treatments effective in OCD have the capacity to desensitize the terminal 5-HT autoreceptor in the orbitofrontal cortex.
Collapse
Affiliation(s)
- P B Bergqvist
- Department of Psychiatry, McGill University, Montréal, Québec, Canada
| | | | | |
Collapse
|
17
|
Sandrini M, Ottani A, Vitale G, Pini LA. Acetylsalicylic acid potentiates the antinociceptive effect of morphine in the rat: involvement of the central serotonergic system. Eur J Pharmacol 1998; 355:133-40. [PMID: 9760027 DOI: 10.1016/s0014-2999(98)00496-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Acetylsalicylic acid and morphine are the most widely distributed and most frequently used drugs in the relief of pain, but their analgesic activity has adverse side-effects. Mixtures containing these two drugs are frequently used to relieve mild to moderate pain despite the paucity of relevant experimental evidence so far published. We set out to study the possible antinociceptive effect of a combination of subactive doses of the two drugs in rats. A combination of low doses of acetylsalicylic acid (50 mg/kg i.p.) and morphine (3 mg/kg s.c.) was administered and the pain threshold was evaluated in the hot-plate and formalin tests, and 5-HT2 receptor binding capacity, 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) levels were measured in the cortex and pontine areas of the brain. The combination of acetylsalicylic acid and morphine had an analgesic effect in both tests that was associated with an increase in 5-HT levels and a decrease in 5-HT2 receptors in the cortex. These effects were either completely abolished or partially prevented by i.p. pretreatment with naloxone (1 mg/kg i.p.). Our results demonstrate that subactive doses of acetylsalicylic acid and morphine can exert analgesic and biochemical effects when given in combination in the rat and suggest an involvement of serotonergic and opiatergic systems.
Collapse
Affiliation(s)
- M Sandrini
- Department of Biochemical Sciences, University of Modena, Italy
| | | | | | | |
Collapse
|
18
|
Agmo A, Belzung C. The role of subtypes of the opioid receptor in the anxiolytic action of chlordiazepoxide. Neuropharmacology 1998; 37:223-32. [PMID: 9680247 DOI: 10.1016/s0028-3908(98)00003-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Previous studies have shown that the opiate antagonist naloxone blocks the anxiolytic-like effects of benzodiazepines in several models of anxiety, including the elevated plus-maze. Although naloxone preferentially binds to the mu opioid receptor, its selectivity is rather low. The opioid receptor subtype important for anxiolytic-like actions of benzodiazepines in the plus-maze remains, therefore, unknown. In the present experiments, the ability of antagonists selective for subtypes of the opioid receptor to block the anxiolytic-like effects of chlordiazepoxide in the elevated plus-maze was evaluated in Swiss mice. Chlordiazepoxide, 5 mg/kg, increased the proportion as well as the number of open arms entries without modifying closed arms entries. Lower doses of the benzodiazepine were ineffective. The mu receptor antagonist beta-funaltrexamine, 10 and 20 mg/kg, the delta antagonist naltrindole, 10 mg/kg, and the kappa antagonist nor-binaltorphimine, 2.5 and 5 mg/kg, were then combined with chlordiazepoxide, 5 mg/kg. beta-funaltrexamine, 10 mg/kg, reduced the effects of the benzodiazepine while the dose of 20 mg/kg completely blocked the effects. Nor-binaltorphimine was ineffective at a dose of 2.5 mg/kg, but completely inhibited the actions of chlordiazepoxide when the dose was 5 mg/kg. Naltrindole was ineffective. None of the antagonists affected plus-maze behavior when administered alone. It was concluded that the mu and kappa receptors are important for the anxiolytic-like actions of chlordiazepoxide in the elevated plus maze.
Collapse
Affiliation(s)
- A Agmo
- Laboratoire de Psychophysiologie, Faculté des Sciences, Université de Tours, France.
| | | |
Collapse
|
19
|
Serotonin monitoring in microdialysate from rat brain by microbore-liquid chromatography with fluorescence detection. Anal Chim Acta 1998. [DOI: 10.1016/s0003-2670(97)00616-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
20
|
Bengtsson F, Bergqvist PB, Apelqvist G. Brain tryptophan perturbation in hepatic encephalopathy: implications for effects by neuropsychoactive drugs in clinical practice. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1997; 420:1-33. [PMID: 9286423 DOI: 10.1007/978-1-4615-5945-0_1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- F Bengtsson
- Department of Clinical Pharmacology, Lund University Hospital, Sweden
| | | | | |
Collapse
|
21
|
Cosford RJ, Vinson AP, Kukoyi S, Justice JB. Quantitative microdialysis of serotonin and norepinephrine: pharmacological influences on in vivo extraction fraction. J Neurosci Methods 1996; 68:39-47. [PMID: 8884611 DOI: 10.1016/0165-0270(96)00057-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The present study was designed to investigate the potential influence of various neuronal processes including uptake, release and metabolism, on the in vivo microdialysis extraction fraction (Ed) of serotonin (5HT) and norepinephrine (NE). Paroxetine administration decreased the Ed of 5HT in the nucleus accumbens from 24 +/- 3 to 18 +/- 0.2% (p < 0.05). Similarly, desipramine infusion reduced the NE Ed from 35 +/- 2 to 26 +/- 1% (p < 0.05). However, perfusion with pargyline or tetrodotoxin had no effect on the Ed of either 5HT or NE. Perfusion with agonists for the 5HT, alpha-adrenergic, D2 and histamine receptors had no effect on the Ed of 5HT. In the same manner, perfusion with the alpha-adrenergic agonists, methoxamine or clonidine, did not affect the Ed of NE. These data are in agreement with experimental results obtained for dopamine in the nucleus accumbens and the theory of quantitative microdialysis which predicts that only changes in the rate of clearance will change Ed of monoamines. These results suggest that, like DA, changes in the Ed for 5HT or NE are indicative of changes in the reuptake of these neurotransmitters. The results also indicate that pharmacological agents which do not affect uptake have no effect on the extraction fraction.
Collapse
Affiliation(s)
- R J Cosford
- Dept. of Chemistry, University of California, Riverside 92521, USA
| | | | | | | |
Collapse
|
22
|
Yoshioka M, Matsumoto M, Togashi H, Saito H. Effect of conditioned fear stress on dopamine release in the rat prefrontal cortex. Neurosci Lett 1996; 209:201-3. [PMID: 8736645 DOI: 10.1016/0304-3940(96)12631-8] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The effects of conditioned fear stress (CFS) on dopamine release in the medial prefrontal cortex were studied by in vivo microdialysis in the rat. CFS (exposure to an environment in which foot-shock had been delivered previously) induced a marked suppression of motility, i.e., freezing behavior. Extracellular concentrations of dopamine in the medial prefrontal cortex were increased by CFS. The increase of dopamine returned to the pretreatment levels when rats were returned to the home cages. Diazepam (0.5 mg/kg, i.p.) suppressed both the CFS-induced freezing behavior and extracellular dopamine levels in the medial prefrontal cortex. These findings suggest that anxiety and dopamine release in the prefrontal cortex might be related.
Collapse
Affiliation(s)
- M Yoshioka
- First Department of Pharmacology, Hokkaido University School of Medicine, Sapporo, Japan
| | | | | | | |
Collapse
|
23
|
Saito H, Matsumoto M, Togashi H, Yoshioka M. Functional interaction between serotonin and other neuronal systems: focus on in vivo microdialysis studies. JAPANESE JOURNAL OF PHARMACOLOGY 1996; 70:203-5. [PMID: 8935715 DOI: 10.1254/jjp.70.203] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In this review, the functional interactions between serotonin (5-HT) and other neuronal systems are discussed with the focus on microdialysis studies in the mammalian brain (mainly rats). 5-HT release is negatively regulated not only by somatodendritic 5-HT1A and terminal 5-HT1B (5-HT1D) autoreceptors but also by alpha 2-adrenergic and mu-opioid heteroreceptors that are located on serotonergic nerve terminals. 5-HT by itself is involved in the inhibitory effects of noradrenaline release and the facilitatory regulation of dopamine release via multiple 5-HT receptors. Acetylcholine release appears to be regulated by inhibitory 5-HT1B heteroreceptors located on cholinergic nerve terminals. Long-term treatment with 5-HT-uptake inhibitors and noradrenaline-uptake inhibitor produces desensitization of 5-HT1A autoreceptors and alpha 2-heteroreceptors, respectively, which may be related therapeutically to the delayed onset of the effects of antidepressants. Some microdialysis studies have predicted that the combination of a 5-HT-uptake inhibitor and 5-HT1A-autoreceptor antagonist might produce much greater availability of 5-HT in the synaptic cleft in terms of much faster induction of subsensitivity of 5-HT1A autoreceptors. Clinical trials based on this hypothesis have revealed that combination therapy with a 5-HT-uptake inhibitor and 5-HT1A-autoreceptor antagonist ameliorated the therapeutic efficacy in depressive patients. Taken together, neurochemical approaches using microdialysis can contribute not only to clarification of the physiological role of the serotonergic neuronal systems but also might be a powerful pharmacological approach for the development of therapeutic strategies.
Collapse
Affiliation(s)
- H Saito
- First Department of Pharmacology, Hokkaido University School of Medicine, Sapporo, Japan
| | | | | | | |
Collapse
|
24
|
Lankford MF, Myers RD. Opiate and 5-HT2A receptors in alcohol drinking: preference in HAD rats is inhibited by combination treatment with naltrexone and amperozide. Alcohol 1996; 13:53-7. [PMID: 8837935 DOI: 10.1016/0741-8329(95)02011-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Amperozide, a 5-HT2A receptor antagonist, and naltrexone, an opiate receptor antagonist, have been shown to suppress volitional drinking of alcohol in experimental animals. The present study examined the effects of the concurrent administration of both drugs on the volitional intake of alcohol in the selectively bred, high alcohol drinking (HAD) rat. Individual preferences for alcohol were determined by a standard 10-day test in which alcohol concentrations were increased from 3% to 30%. Following a 4-day predrug test during which water together with a maximally preferred concentration of 7% to 20% was offered to each HAD rat, amperozide and naltrexone were injected SC over a second 4-day period as follows: 1) amperozide at 1600 h and naltrexone at 2200 h; 2) the same drugs but in reversed temporal order; and 3) amperozide and naltrexone administered simultaneously at 1600 and 2200 h. Thereafter, alcohol preference testing continued for a third 4-day period. The alternate delivery of both drugs attenuated significantly the absolute g/kg and proportional intakes of alcohol in the HAD rats, whereas the saline vehicle was without effect. Although the simultaneous administration of naltrexone and amperozide produced an even greater decline in alcohol intake, without side effects on food and water intakes or on body weight, some residual drinking of alcohol persisted. Nevertheless, the results corroborate our previous findings on the suppression of alcohol drinking by antagonists of opiate and 5-HT2A receptors. Because amperozide and naltrexone together reduce the apparent reinforcing property of alcohol, the theory is supported that the addictive liability to alcohol is underpined by multiple receptor subtypes within the mesolimbic and other systems in the brain.
Collapse
Affiliation(s)
- M F Lankford
- Department of Pharmacology, East Carolina University, Greenville, NC 27858, USA
| | | |
Collapse
|
25
|
Besson A, Privat AM, Eschalier A, Fialip J. Effects of morphine, naloxone and their interaction in the learned-helplessness paradigm in rats. Psychopharmacology (Berl) 1996; 123:71-8. [PMID: 8741957 DOI: 10.1007/bf02246283] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The aim of this study was to investigate the possible involvement of the mu-opioid system on the learned-helplessness paradigm, an experimental model of depression, in rats. In this test, rats were first exposed to inescapable foot-shocks (IS); 48 h later, they were submitted to a daily shuttle-box session (30 trials) for 3 consecutive days. Avoidance responses, escape failures and animal activity during each intertrial interval were recorded. Twice daily injections of morphine (0.25-8 mg/kg per day, SC), a mu-opioid agonist, reduced the increased escape failures induced by IS, as did tricyclic antidepressants. Significantly higher intertrial activity was observed in rats treated with morphine (2-8 mg/kg per day) compared with their associated control groups. Naloxone (1 and 2 mg/kg, IP), a mu-opioid antagonist, injected 10 min before each shuttle-box session impaired escape behavior in non-stressed rats and worsened the escape deficit induced by IS. Morphine-induced improvement of escape behavior and increase in intertrial activity were clearly reversed by a low inactive dose of naloxone (0.5 mg/kg). These results suggest that mu-opioid receptor mediation is involved in the deleterious effects of uncontrollable stress.
Collapse
Affiliation(s)
- A Besson
- Laboratoire de Pharmacologie, Faculte de Pharmacie, Clermont-Ferrand, France
| | | | | | | |
Collapse
|
26
|
Williams FG, Mullet MA, Beitz AJ. Basal release of Met-enkephalin and neurotensin in the ventrolateral periaqueductal gray matter of the rat: a microdialysis study of antinociceptive circuits. Brain Res 1995; 690:207-16. [PMID: 8535838 DOI: 10.1016/0006-8993(95)00554-4] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The periaqueductal gray (PAG) contains neural circuits that participate in descending antinociception. Anatomical and electrophysiological evidence suggests that these circuits might employ opioid peptides and GABA in series to remove a tonic inhibition of descending PAG output neurons. The present studies examined the release of the antinociceptive peptides Met-enkephalin and neurotensin in the ventrolateral PAG, and investigated the interaction between GABA and Met-enkephalin release. In awake and freely moving rats the ventrolateral PAG was dialysed using 25 ga. concentric probes. Basal release of peptide in 12 min or 40 min fractions was determined using radioimmunoassays. To establish how the ventrolateral PAG responds to nociception, dialysis was performed following unilateral hindpaw inflammation using Complete Freund's Adjuvant. Twenty-four hours after inflammation was induced, neurotensin release was increased 133% and Met-enkephalin release was increased 353% compared to control animals. Seven days after inflammation was induced, neurotensin release declined precipitously, while basal Met-enkephalin release remained elevated 313% above controls. Thus, unlike enkephalin, increased basal neurotensin release is not sustained with persistent tonic nociception. In addition, we confirmed in normal animals that the ventrolateral PAG is induced to release Met-enkephalin by systemic morphine. A 43% increase in basal Met-enkephalin release was observed immediately following a 12 mg/kg i.p. morphine injection. Morphine should have the opposite effect (inhibit peptide release) if it acts directly on the enkephalinergic neurons. Thus, we examined the hypothesis that GABAergic interneurons in the PAG mediated morphine-stimulated enkephalin release. When the GABAantagonist bicuculline (0.25 microM to 25 microM) was co-infused with the dialysis medium, Met-enkephalin release increased in a dose-dependent fashion and peaked 68% above pre-infusion levels. These data elucidate the reciprocal inhibitory relationship between GABA and enkephalin in the ventrolateral PAG. We hypothesize that, when nociception induces Met-enkephalin release within this region, the tonic GABAergic inhibition is overcome, resulting in greater sensitivity of PAG enkephalinergic neurons. Ultimately, this enhanced enkephalin release should result in greater excitability of the descending PAG output neurons that are responsible for antinociception.
Collapse
Affiliation(s)
- F G Williams
- Department of Veterinary Biology, College of Veterinary Medicine, University of Minnesota, St. Paul 55108, USA
| | | | | |
Collapse
|
27
|
Tao R, Auerbach SB. Involvement of the dorsal raphe but not median raphe nucleus in morphine-induced increases in serotonin release in the rat forebrain. Neuroscience 1995; 68:553-61. [PMID: 7477965 DOI: 10.1016/0306-4522(95)00154-b] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In vivo microdialysis was used to determine if morphine produces increases in extracellular serotonin in specific brain sites. With citalopram included in the dialysis solution to block reuptake, serotonin was measured in 11 brain sites of unanesthetized rats. After systemic morphine (10 mg/kg, s.c.), increases in extracellular serotonin were observed in the nucleus accumbens, amygdala, frontal cortex, striatum, thalamus, hypothalamus and ventral hippocampus. These seven areas are innervated either by dorsal raphe nucleus projections alone, or by projections from both dorsal and median raphe nucleus. In contrast, serotonin was not significantly increased in the medial septal nucleus and dorsal hippocampus. These two areas are selectively innervated by projections from the median raphe nucleus. After systemic morphine, serotonin was increased in the dorsal raphe nucleus, but not in the medial raphe nucleus. Local infusion of morphine through a microdialysis probe in the dorsal raphe nucleus induced a dose-dependent increase of serotonin in the nucleus accumbens, but not in the medial septum. In contrast, infusion of morphine into the median raphe nucleus had little effect on serotonin in either the nucleus accumbens or septum. Infusion of morphine into either the dorsal or median raphe nucleus elicited increased behavioral activity and hyperthermia. These data provide evidence that morphine acts in the area of the dorsal raphe nucleus, but not the median raphe nucleus, to enhance serotonin release in specific forebrain sites, and that the increases in serotonin in the dorsal raphe nucleus projection sites are not an indirect effect of changes in behavioral state or body temperature.
Collapse
Affiliation(s)
- R Tao
- Department of Biological Sciences, Rutgers University, Piscataway, NJ 08855-1059, USA
| | | |
Collapse
|
28
|
Numazawa R, Yoshioka M, Matsumoto M, Togashi H, Kemmotsu O, Saito H. Pharmacological characterization of alpha 2-adrenoceptor regulated serotonin release in the rat hippocampus. Neurosci Lett 1995; 192:161-4. [PMID: 7566640 DOI: 10.1016/0304-3940(95)11635-a] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The purpose of the present study was to confirm the functional regulation by alpha 2-adrenoceptors of the release of serotonin (5-HT) from the rat hippocampus in vivo. Under several pharmacological conditions, extracellular levels of 5-HT were estimated by assaying its concentrations in the perfusate by high performance liquid chromatography with electrochemical detection. Extracellular 5-HT in the hippocampus was reduced by tetrodotoxin (10 microM) co-perfusion, but increased by perfusion of a selective 5-HT re-uptake inhibitor, fluoxetine (10 microM). Addition of potassium (K+, 120 mM) to the perfusion fluid evoked an approximately 3-fold increase in 5-HT release. When the alpha 2-adrenoceptor agonist UK14,304 (0.1-10 microM) was added to the perfusion solution, the K(+)-evoked 5-HT release was significantly inhibited in a concentration-dependent manner. This inhibitory action of UK14,304 was reversed by pretreatment with an alpha 2-adrenoceptor antagonist, idazoxan (5 mg/kg, i.p.). In rats which were catecholaminergically denervated with 6-hydroxydopamine, UK14,304 (10 microM) still inhibited the K(+)-evoked 5-HT release. Treatment with pertussis toxin (PTX) did not alter the K(+)-evoked release of 5-HT but abolished the inhibitory effect of UK14,304. These findings suggest that 5-HT release is functionally modulated via alpha 2-adrenoceptors located on the serotonergic nerve terminals in the rat hippocampus and furthermore, the possibility that the inhibitory of alpha 2-adrenoceptors is linked to G-proteins which are substrates of PTX.
Collapse
Affiliation(s)
- R Numazawa
- Department of Anesthesiology, Hokkaido University School of Medicine, Sapporo, Japan
| | | | | | | | | | | |
Collapse
|
29
|
Yoshioka M, Matsumoto M, Togashi H, Saito H. Effects of conditioned fear stress on 5-HT release in the rat prefrontal cortex. Pharmacol Biochem Behav 1995; 51:515-9. [PMID: 7667378 DOI: 10.1016/0091-3057(95)00045-x] [Citation(s) in RCA: 126] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The effects of conditioned fear stress (CFS) on 5-HT release in the medial prefrontal cortex were studied by in vivo microdialysis. CFS (exposure to an environment in which foot-shock had been delivered previously) induced a marked suppression of motility-that is, freezing behavior. The extracellular concentration of 5-HT in the medial prefrontal cortex increased during this freezing behavior, but no significant changes were observed in the concentration of its metabolite, 5-HIAA. The increased 5-HT concentration returned to pretreatment levels when the animals were returned to their home cages. Diazepam (0.5 mg/kg, intraperitoneally) reduced the CFS-induced freezing behavior and prevented the increases in extracellular 5-HT levels. A 5-HT3 receptor antagonist, tropisetron (10 and 100 micrograms/kg), also inhibited both the CFS-induced increase in 5-HT release and the freezing behavior. These findings suggest that there is a relationship between anxiety and 5-HT release in the prefrontal cortex and that the 5-HT3 receptor antagonist tropisetron might have anxiolytic properties.
Collapse
Affiliation(s)
- M Yoshioka
- First Department of Pharmacology, Hokkaido University School of Medicine, Sapporo, Japan
| | | | | | | |
Collapse
|
30
|
Matsumoto M, Yoshioka M, Togashi H, Hirokami M, Tochihara M, Ikeda T, Smith CB, Saito H. mu-Opioid receptors modulate noradrenaline release from the rat hippocampus as measured by brain microdialysis. Brain Res 1994; 636:1-8. [PMID: 8156397 DOI: 10.1016/0006-8993(94)90169-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The modulation of noradrenaline (NA) release via presynaptic opioid receptors in the hippocampus of freely moving rats was studied by the use of brain microdialysis. Extracellular levels of NA were estimated by assaying its concentrations in the perfusion fluid using high-performance liquid chromatography (HPLC) with electrochemical detection (ECD). Spontaneous NA levels were reduced by tetrodotoxin (1 microM) co-perfusion and were increased by peripheral administration of desipramine (5 and 10 mg/kg, i.p.). Addition of potassium (K+, 60 and 120 mM) to the perfusion fluid evoked a concentration-dependent release of NA. K+ (120 mM)-evoked NA release was markedly reduced by removal of calcium (Ca2+) from the perfusion fluid. These results indicate that both the spontaneous and the K(+)-evoked NA release measured by the use of brain microdialysis coupled with HPLC-ECD can be used as indices of neuronal release from the noradrenergic nerve terminals. A mu-opioid receptor agonist, morphine (0.01-10 microM), when co-perfused with K+ (120 mM), produced a reduction of K(+)-evoked NA release in a concentration-dependent manner. Neither co-perfusion with a high concentration of [D-Pen2, D-Pen5]-enkephalin (DPDPE) (10 microM), an agonist selective for delta-opioid receptors, nor with U-69593 (10 microM), an agonist selective for kappa-opioid receptors, modified the K+ (120 mM)-evoked release of NA. Morphine-induced (1 microM) inhibition of NA release was blocked by a mu-opioid receptor antagonist, naltrexone (3 and 9 mg/kg, i.p). Naltrexone by itself did not alter the spontaneous NA levels or the K(+)-evoked NA release.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- M Matsumoto
- First Department of Pharmacology, Hokkaido University School of Medicine, Sapporo, Japan
| | | | | | | | | | | | | | | |
Collapse
|
31
|
In Vivo Sampling and Administration of Hormone Pulses in Rodents. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/b978-0-12-185289-4.50014-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|